The title should really be game architecture (with Unreal Engine 4). It's not so much on how to architect a game engine as it is about structuring game code in general and UE4 game code in particular.
I find navigating these slides quite difficult, shouldn't a lecture have a linear narrative?
Instead, I can use the left/right/down/up buttons to go through the slides in a fashion I cannot understand (if I just use the right arrow in the Intro, it goes 1 2 3 5 8...).
For a presentation on actual game engine architecture, I can really recommend the set of talks on the stingray engine https://www.youtube.com/watch?v=LgbSYxf9vT4